Activation of Zr0.8Ti0.2Mn0.4V0.6Ni electrode by hot-charging treatment and its cycling performance for Ni-MH secondary battery

An electrode with a composition Zr0.8Ti0.2Mn0.4V0.6Ni was activated by hot-charging treatment at various current densities and for different times, and then its cycling performance was examined. The first discharge capacity increases as the hot-charging times and the current density increase. The hot-charging and the charge-discharge cycling create cracks on the surface of the particles and make the particles smaller, leading to the exposure of the clean surfaces of the particles. The form of the cycling performance curve of the alloy with small and large particles is suggested. The surface of the electrode, analyzed by energy-dispersive spectrometry (EDS), shows an gradual increase in the atomic ratio of Ni as the number of cycle increases. The electrolyte after 50 cycles analyzed by ICP have relatively large concentrations of V and Zr